Software defined networking (SDN) is one of the most indispensable parts of software defined data center (SDDC). SDN provides an abstraction of physical networking infrastructure and defines logical networking devices such as logical switches, logical routers, etc. Similar to physical networking devices, these logical devices provide functionalities that are close to physical ones and are transparent to virtual machines (VMs) in the SDDC.
Logical devices provide benefits that the physical devices could not furnish. For instance, logical devices could be linked with each other by just defining the topology configuration while physical devices need physical cables to be attached. Logical devices could be distributed entities while physical devices must be single entities. Since logical devices are software driven, distributed solutions are widely preferred and used by the SDN in the SDDC.
Many applications in a data center require applying rules that are based on network addresses. For instance, entity based firewall rules for a distributed firewall are configured based on network addresses. The firewall rules for different logical entities are then enforced by a forwarding element (or logical switch) based on the source and destination network addresses in the packet headers. There is currently no efficient way of translating logical entities connected to a forwarding element into network addresses for consumption by the applications that require the logical entities' network addresses.